Construction method for overhead jacking of multi-track existing railway of frame bridge

ABSTRACT

Disclosed is a construction method for overhead jacking of a multi-track existing railway of a frame bridge. By means of construction modes of transition overhead construction-dewatering construction-formal overhead and two-end opposite jacking and middle cast-in-place, the risk caused by the groundwater level to a dig-hole pile is directly avoided. The overall construction scheme for the overpass pipe section follows the principle of segmented construction and line production, a jacking part of the overpass is firstly constructed, and after the jacking part is in place, a middle frame is cast in place, which guarantees not only the railway operation but also the construction period quality, and thus good economic benefits and construction guidance significance are achieved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit and priority of Chinese Patent Application No. 202111153618.8, filed with the China National Intellectual Property Administration on Sep. 29, 2021. The entire disclosure of the above application is incorporated herein by reference.

FIELD

The present disclosure belongs to the technical field of underpass engineering construction, and in particular relates to a construction method for overhead jacking of a multi-track existing railway of a frame bridge.

INTRODUCTION

With the increase of urbanization in China, in order to connect and coordinate the development of the regions on both sides of the city railroad, a considerable part of municipal planning roads need to cross the existing railway. The construction technology for the underpass existing railway has gradually matured, but with this comes an increase in construction requirements. In the future, the existing construction technology will face severe challenges when dealing with the problem of underpass existing railway with complicated conditions.

In the overhead reinforcement construction for the existing railway, the roadbed structure and train operation will be greatly affected. After long-time engineering practice, although the overhead reinforcement technology for the underpass existing railway has been greatly improved, surrounding structures and soil mass may still be disturbed by the field construction, leading to displacement deformation of overhead structures, roadbeds and like to different degrees, roadbeds and like. Therefore, the stability of the existing railway must be maintained to the maximum extent during construction to reduce the safety risks of the existing railway in the overhead construction. Therefore, how to reduce the influence of surrounding environment and existing roadbeds in the construction and how to select overhead jacking construction scheme to satisfy requirements of the railway safety and maximize the benefit at the same time have become a key problem in overhead jacking engineering. Especially for the multi-track existing operation railways, the overhead jacking construction is more complex. Therefore, in the overhead reinforcement construction for the existing railway, the reasonable overhead jacking construction scheme and model selection thereof are of a deep practical significance.

SUMMARY

To overcome the problem in the prior art, an objective of the present disclosure is to provide a construction method for overhead jacking of a multi-track existing railway of a frame bridge. In accordance with the construction method, in the frame bridge overpass construction process, the existing railway with an underpass below is normally open to traffic without affecting the safety of the traffic train, the problem that in the existing engineering, the problem that large-span overhead construction cannot be achieved in the overhead jacking process of the multi-track existing railway is solved, and the construction safety is high. After the construction is completed, steel members such as the longitudinal beams, the steel sleepers and the horizontal lifting beams can be recycled, and thus the construction cost is low, and the safety is high.

To achieve the objective above, the technical solution adopted by the present disclosure is as follows:

A construction method for overhead jacking of a multi-track existing railway of a frame bridge comprises the specific steps as follows:

one, excavating working foundation pits 10 on both sides of the multi-track existing railway;

two, prefabricating jacking pipe sections 1 in the working foundation pits 10;

three, performing transition overhead;

four, dewatering by a broached groove;

five, performing hole digging construction for a formal overhead pile 6;

six, after the step five is completed, jacking, by a jack, the prefabricated jacking pipe sections 1 into an overhead system from both sides of the multi-track existing railway in a direction perpendicular to the existing railway;

seven, performing overhead conversion in a mode of pile breaking while jacking, after the jacking pipe sections 1 on both sides of the multi-track existing railway are jacked in place, replacing an overhead pile with the jacking pipe sections 1 to serve as a supporting structure, and forming a construction space of a middle cast-in-place pipe section 2 by erecting a horizontal lifting beam 9; and then casting a pipe section 2 in place between the jacking pipe sections 1; and

eight, after the pipe section 2 is cast in place, regarding that the construction of the frame bridge underpass multi-track existing railway is completed, dismounting overhead equipment to recover the normal operation of the railway.

In the step one and step two, a side wall of the working foundation pit 10 is provided with formwork concrete.

The specific method of transition overhead in the step three is as follows: digging a pile hole below the existing railway according to the load design, with a hole digging depth above groundwater level; then casting a temporary overhead pile 3, and erecting an upper overhead component by taking the pile top of the temporary overhead pile 3 as a fulcrum.

The upper overhead component comprises longitudinal beams 7 and steel sleepers 8.

The specific method in the step four is as follows: after the transition overhead in the step three is completed, constructing working grooves 4 below the existing railway and between the temporary overhead piles 3 in each row, constructing foundation pit fender piles 5 and dewatering wells 12 by using working faces in the working grooves 4, and then performing dewatering to enable the ground water level to reach the designed water level.

In the step four, the dewatering wells 12 are distributed at both sides of the multi-track existing railway and in the working grooves 4.

The dewatering wells 12 are mechanically constructed.

The specific method in the step five is as follows: digging a pile hole, underneath the temporary overhead pile 3, below the existing railway according to the load design, with a hole digging depth below the groundwater level, and then casting the formal overhead pile 6, and arranging a horizontal lifting beam 9 in a penetrating manner with the pile top of the formal overhead pile 6 as a fulcrum so as to form an overhead system.

The formal overhead pile 6 is constructed by a manual hole digging method.

The jacking pipe section 1 and the cast-in-place pipe section 2 each comprise a pipe section roof 1-1, a pipe section baseplate 1-2, pipe section side walls 1-3 and a pipe section middle partition wall 1-4; the pipe section roof 1-1 is in contact with an upper load, the pipe section baseplate 1-2 is in contact with the ground, the pipe section side walls 1-3 and the pipe section middle partition wall 1-4 are connected to the pipe section roof 1-1 and the pipe section baseplate 1-2, and the pipe section middle partition wall 1-4 is located between the pipe section side walls 1-3 and is parallel to the pipe section side walls 1-3.

One side of the pipe section baseplate 1-2 of the jacking pipe section 1 is provided with a triangular correction block 11, such that the jacking pipe section 1 and the existing railway are constructed in a skew jacking manner.

Compared with the prior art, the present disclosure has the following beneficial effects:

An overhead concept of transition overhead—dewatering construction-formal overhead and a construction mode of two-end opposite jacking and middle cast-in-place are provided. In accordance with the construction concept and the construction mode, in the frame bridge overpass construction process, the existing railway with an underpass below is normally open to traffic without affecting the safety of the traffic train. The overhead reinforcement structures are mostly prefabricated steel structures, which can be recovered after the construction is completed, thus the materials can be recycled, and the construction cost is low. The risk caused by the groundwater level to a dig-hole pile can be directly avoided through the optimal design of the construction scheme. The overall construction scheme for the overpass pipe section follows the principle of segmented construction and line production, a jacking part of the overpass is firstly constructed, and after the jacking part is in place, a middle frame is cast in place, which guarantees not only the railway operation but also the construction period quality, and thus good economic benefits and construction guidance significance are achieved.

DRAWINGS

FIG. 1 is a schematic diagram of a plane structure in accordance with the present disclosure;

FIG. 2 is a schematic diagram of a cross-sectional structure in accordance with the present disclosure;

FIG. 3 is a sectional diagram of a broached groove in accordance with the present disclosure;

FIG. 4 is a schematic diagram of a longitudinal section structure in accordance with the present disclosure; and

FIG. 5 is a schematic diagram of jacking construction of a pipe section of a frame bridge in accordance with the present disclosure,

In the drawings: 1—jacking pipe section; 2—cast-in-place pipe section; 3—temporary overhead pile; 4—working groove; 5—foundation pit fender pile; 6—formal overhead pile; 7—longitudinal beam; 8—steel sleeper; 9—horizontal lifting beam; 10—working foundation pit; 11, triangular correction block; 12—dewatering well; 13—back wall; 14—jack; 15—working baseplate; 1-1—pipe section roof; 1-2—pipe section baseplate; 1-3—pipe section side wall; 1-4—pipe joint middle partition wall.

DETAILED DESCRIPTION

The following clearly and completely describes the technical solutions in the present disclosure with reference to the accompanying drawings. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

The following clearly and completely describes the technical solutions in the present disclosure with reference to the accompanying drawings. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

Referring to FIG. 1 to FIG. 5 , a construction method for overhead jacking of a multi-track existing railway of a frame bridge, which comprises the following specific steps:

A construction method for overhead jacking of a multi-track existing railway of a frame bridge comprises the specific steps as follows:

1. Working foundation pits 10 are excavated at both sides of the multi-track existing railway, wherein the sidewall of each working foundation pit 10 is made of formwork concrete, which not only guarantees the stability of the foundation pit, but also serves as a reaction wall for pipe section jacking of the frame bridge.

2. The jacking pipe sections 1 are prefabricated in the working foundation pits 10.

3. A pile hole is dug below the existing railway according to the load design, with a hole digging depth above groundwater level; then a temporary overhead pile 3 is casted, and an upper overhead component is erected with the pile top of the temporary overhead pile 3 as a fulcrum.

4. Dewatering by a broached groove: after the transition overhead in the step three is completed, working grooves 4 are constructed below the existing railway and between the temporary overhead piles 3 in each row, foundation pit fender piles 5 and dewatering wells 12 are constructed by using working faces in the working grooves 4, and then dewatering is carried out to enable the ground water level to reach the designed water level. The dewatering wells 12 are distributed at both sides of the multi-track existing railway and in the working grooves, and the dewatering wells 12 are mechanically constructed.

5. A pile hole is dug beneath the temporary overhead pile 3 below the existing railway, with a hole digging depth below the groundwater level, and then the formal overhead pile 6 is casted, and a horizontal lifting beam 9 is arranged in a penetrating manner with the pile top of the formal overhead pile 6 as a fulcrum so as to form an overhead system.

6. After the step five is completed, the prefabricated jacking pipe sections 1 are jacked in the overhead system from both sides of the multi-track existing railway by using a jack. A triangular correction block 11 is arranged at one side of the pipe section baseplate 1-2 of the jacking pipe section 1, such that the jacking pipe section 1 and the existing railway are constructed in a skew jacking manner.

7. Overhead conversion is carried out by means of pile breaking while jacking, after the jacking pipe sections 1 on both sides of the multi-track existing railway are jacked in place, the jacking pipe sections serve as a supporting structure by replacing the overhead pile, a construction space of a middle cast-in-place pipe section 2 is formed by erecting the horizontal lifting beam 9; and a pipe section 2 is cast in place between the jacking pipe sections 1;

8, after the pipe sections 2 are cast in place, regarding that the construction of the frame bridge underpass multi-track existing railway is completed, dismounting the overhead equipment to recover the normal operation of the railway. 

What is claimed is:
 1. A construction method for overhead jacking of a multi-track existing railway of a frame bridge, comprising the specific steps as follows: one, excavating working foundation on both sides of the multi-track existing railway; two, prefabricating jacking pipe sections in the working foundation pits; three, performing transition overhead; four, dewatering by a broached groove; five, performing hole digging construction for a formal overhead pile; six, after the step five is completed, jacking, by a jack, the prefabricated jacking pipe sections into an overhead system from both sides of the multi-track existing railway in a direction perpendicular to the existing railway; seven, performing overhead conversion in a mode of pile breaking while jacking, after the jacking pipe sections on both sides of the multi-track existing railway are jacked in place, replacing an overhead pile with the jacking pipe sections to serve as a supporting structure, and forming a construction space of a middle cast-in-place pipe section by erecting a horizontal lifting beam; and then casting a pipe section in place between the jacking pipe sections; and eight, after the pipe section is cast in place, regarding that the construction of the frame bridge underpass multi-track existing railway is completed, dismounting overhead equipment to recover the normal operation of the railway.
 2. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 1, wherein in the step one and step two, a side wall of the working foundation pit is provided with formwork concrete.
 3. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 1, wherein the specific method of transition overhead in the step three is as follows: digging a pile hole below the existing railway according to the load design, with a hole digging depth above groundwater level; then casting a temporary overhead pile, and erecting an upper overhead component by taking the pile top of the temporary overhead pile as a fulcrum.
 4. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 3, wherein the upper overhead component comprises longitudinal beams and steel sleepers.
 5. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 1, wherein the specific method in the step four is as follows: after the transition overhead in the step three is completed, constructing working grooves below the existing railway and between the temporary overhead piles in each row, constructing foundation pit fender piles and dewatering wells by using working faces in the working grooves, and then performing dewatering to enable the ground water level to reach the designed water level.
 6. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 5, wherein in the step four, the dewatering wells are distributed at both sides of the multi-track existing railway and in the working grooves; the dewatering wells are mechanically constructed.
 7. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 1, wherein the specific method in the step five is as follows: digging a pile hole, underneath the temporary overhead pile, below the existing railway according to the load design, with a hole digging depth below the groundwater level, and then casting the formal overhead pile, and arranging a horizontal lifting beam in a penetrating manner with the pile top of the formal overhead pile as a fulcrum so as to form an overhead system.
 8. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 7, wherein the formal overhead pile is constructed by a manual hole digging method.
 9. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 1, wherein in the step seven, the jacking pipe section and the cast-in-place pipe section each comprise a pipe section roof, a pipe section baseplate, pipe section side walls and a pipe section middle partition wall; the pipe section roof is in contact with an upper load, the pipe section baseplate is in contact with the ground, the pipe section side walls and the pipe section middle partition wall are connected to the pipe section roof and the pipe section baseplate, and the pipe section middle partition wall is located between the pipe section side walls and is parallel to the pipe section side walls.
 10. The construction method for overhead jacking of multi-track existing railway of a frame bridge according to claim 9, wherein one side of the pipe section baseplate of the jacking pipe section is provided with a triangular correction block, such that the jacking pipe section and the existing railway are constructed in a skew jacking manner. 